Cosmic Explorer

ESTES Model #2421


Search the cosmos with the Estes Cosmic Explorer! This unique sport rocket has styling and power that’s BIG on performance. The Cosmic Explorer is an easy to assemble, high tech marvel on the launch pad. Powered with standard Estes engines, this adventurer can easily top the 1,000 foot level, then returns safely on a large 18 inch pre-assembled parachute.

This easy to build, Skill Level 1 rocket is over 2 feet tall! It features quality body tubes, a super big balsa nose cone, laser cut wood fins and easy to apply waterslide decals. This action-packed rocket is great for beginners who are looking for awesome, high altitude performance in a remarkably streamlined rocket!

Additional Information

  • Length: 24.0″
  • Diameter: 1.33″
  • Weight: 2.7oz.
  • Fins: Balsa
  • Recovery: Parachute
  • Decal: Waterslide
  • Recommended Motors:
    • B4-4, B6-4, C6-5


Photo Gallery

Build History

  • 08/21/2010 – Purchased Estes #2421 Cosmic Explorer from Hobby Lobby in Columbus, IN for $13.19 (Retail $21.99).
  • 08/22/2010 – Took pictures of package front and back.
  • 09/20/2019 – Opened package and took pictures and measurements of components. Scanned instructions, decal, fins, nose cone, stock, and motor mount instructions.
  • 09/24/2019 – Sanded fin balsa stock sheet. Removed fins and rounded leading edges with 220 grit sandpaper. Marked motor mount tube at 1″ & 2-1/2″ from aft end. Glued centering rings at these positions. It was noted that the centering rings were to close together and the fins would not fit between them therefore an new motor mount tube was made. Using the fin slots as a guide the new centering rings were placed at the proper positions so the fins would fit. Joints were filleted with yellow glue.
  • 09/25/2019 – The motor mount assembly was glued into the aft of the body tube so the fins will fit into the body tube slots. Glued fins through slots onto the motor mount tube with yellow glue. glued screw eye into balsa nose cone. Glued tube coupler into forward end of main body tube.
  • 09/26/2019 – glued shock cord to shock cord mount and inside upper body tube recessed at least 2″ from the forward edge. Glued launch lug 4″ from aft end of main body tube along reference line. Filleted joints.
  • 09/29/2019 – Spray painted model with white primer.
  • 04/18/2021 – Spray painted white primer onto model again.
  • 07/22/2021 – Spray painted white primer onto model a third time.
  • 09/25/2023 – Spray painted model with Rust-oleum #328373 High Gloss White.
  • 09/27/2023 – Masked model so black paint could be applied.
  • 09/28/2023 – Spray painted Rust-oleum #328374 High Gloss Black.
  • 11/03/2023 – sanded balsa fins with 120 & 220 grit sandpaper and entire model with 600 grit sandpaper. Wiped model with alcohol wiper.
  • 11/04/2023 – Spray painted with Rust-oleum # 328373 High Gloss White. Removed masking.
  • 12/08/2023 – Cut decals from decal sheet and applied to model using photo card as guide. This completes construction of Estes #2421 Cosmic Explorer model rocket. Took picture of model.